The invention relates to an x-ray diagnostic system comprising a tomograph with which means are associated for the selection of the path of movement of the photographic exposure unit (through which selection the running time of photographic exposure unit is also determined), the photographic exposure unit including an x-ray tube and image layer (or film) carrier, and the system further comprising an x-ray diagnostic generator for supplying the x-ray tube and which contains input means for setting the photographic exposure data.
An x-ray diagnostic system of this type is described in the German OS No. 21 16 705. In the case of this x-ray diagnostic system, four different paths of movement, and, accordingly, four different running times of the photographic exposure unit are selectable. The x-ray diagnostic generator permits the adjustment of the mAs-product and the x-ray tube voltage for a photographic exposure.
Optimum photographic exposures are obtained only if the photographic exposure time during which high voltage is supplied to the x-ray tube is approximately equal to the running time which elapses during movement of the photographic exposure unit over the selected path. However, in practice, in the known x-ray diagnostic system the photographic exposure time will always be somewhat shorter than the running time of the photographic exposure unit, since the x-ray tube must be reliably switched off before the movement of the photographic exposure unit is terminated.